The present invention relates to a tire/wheel assembly and a run-flat support member, and more specifically, to a tire/wheel assembly and a run-flat support member in which both workability of tire-to-rim fit and run-flat durability have been achieved.
In response to demands from the market, there have been many technologies proposed to allow a vehicle to run urgently for several hundreds of kilometers even when a pneumatic tire is punctured while the vehicle is running. Amongst these many proposals, technologies proposed in Japanese Patent Laid-Open Publication No. 10-297226 and Published Japanese Translation of a PCT Application No. 2001-519279 enable run-flat traveling by fitting a core onto a rim in the inner side of a cavity of a pneumatic tire that is assembled to the rim, and by supporting the punctured tire using the core.
The foregoing run-flat core includes a circular shell in which the outer circumferential side thereof serves as a support surface and the inner circumferential side thereof is opened so as to form two leg portions. Also, elastic rings are fitted to both leg portions of the circular shell, and thus the run-flat core is supported on the rim through the elastic rings. By using this run-flat core, a conventional wheel and rim can be used as they are without any particular modifications. Therefore, the run-flat core is advantageously adopted without causing confusion in the market.
Tire-to-rim fit operations of the above tire/wheel assembly (wheel) are as follows. A run-flat core is inserted into the inside of a pneumatic tire, and pressure is given to the inside of the tire having the core therein by air inflation. While the tire is inflated, beads of the pneumatic tire and inner edges of the run-flat core are slid on rim seats together until they are ultimately fixed to respective specified positions. However, since a cavity inside the run-flat core and a cavity between the pneumatic tire and the run-flat core are maintained as mutually independent spaces, it is difficult to balance inner pressure of both cavities during inflation. Therefore, there has been a problem that the workability of tire-to-rim fit is unstable.
If a through-hole is provided in the circular shell so as to allow both cavities to communicate with each other, both cavities can constantly maintain the same inner pressure during an inflating operation. Consequently, the workability of tire-to-rim fit is improved, thus facilitating the operation of the same. However, the fact that the through-hole is provided in the circular shell causes a problem that intensive stresses are applied on the through-hole during run-flat traveling, and thus the circular shell is easily damaged in early stages. Hence, the durability of the run-flat core is lowered.
Specifically, there has been a problem that it is hard to achieve both workability of tire-to-rim fit of a tire/wheel assembly (wheel) and durability of the same.